ELECTROREFLECTANCE ANISOTROPY AT THE WSE2 LAYER SEMICONDUCTOR

The scanning microscope for semiconductor characterization (SMSC) was used to perform electrolyte electroreflectance (EER) measurements at t he n-WSe2-iodide interface. The field dependence of the EER spectra wa s found to be in agreement with that predicted by Blossey's excitonic theory. A significant shift towards lower energies, without shape modi fication, was observed in EER spectra of defective (stepped) zones wit h respect to those corresponding to smooth regions. This effect was ex plained in terms of the optical anisotropy which characterizes the WSe 2 layer semiconductor. The ground exciton energy (E1) of the smallest direct transition at the K point of the Brillouin zone was found to be higher along the c axis than perpendicular to it. A video image of th e E1 surface distribution was obtained from SMSC measurements of the E ER signal at constant wavelength.